Infidelity gene: Sensational, but science?
By Wendy McElroy
web posted December 6, 2004
The Scotsman, a respected UK newspaper, announced late last
month, "Cheating Women May Blame Their Genes."
A yet to be published study from London found that genetic
make-up constitutes an "important influence" in women's infidelity
"with a heritability of 41 percent." But studies purporting to
quantify the genetic basis of complex human behavior should be
approached with caution.
The media has not been displaying such caution. News of the
"infidelity gene" quickly hit headlines around the world: the New
York Post declared, "Cheating's in the DNA for Ladies."
Health Talk Canada stated, "Some Women Cheat Because It's
In Their Genes." The Melbourne Herald Sun informed its
readers, "One in five women cheat - and it's genetic."
India, Ireland, South Africa....
From the superficiality of reports, the media seems to have relied
on a brief press release rather than the study itself. (The study is
due out in the December Twin Research, a scientific journal.) No
analysis of methodology or other key factors has been apparent,
for instance.
The press release itself should have raised questions. For
example, lead researcher Professor Tim Spector states that the
study "lends support to evolutionary psychologists' theories on
the origins of human behaviour."
As the author of the popular 2003 book Your Genes Unzipped:
How Your Genetic Inheritance Shapes Your Life, Spector has
both a bias and a vested interest in proving these theories true.
Spector also declares, "this study justifies additional genetic and
molecular research on human sexual behaviour," thus leading me
to wonder if the study is a preamble to increasing the funding to
his research.
Neither observation invalidates the study; they merely provide
reason for enhanced scrutiny.
Based on the press release, I can neither evaluate the study nor
validate its conclusions by uncritically repeating them. But I can
offer some of the questions and points of skepticism with which
I'll approach the full study when it is readily available.
One concern is the political atmosphere that surrounds current
theories of human behavior and the political uses of such
"research."
The Spector study is part of the "nature versus nurture" debate,
which has been defined as "a popular phrase used to describe
debates over the relative degrees to which one's genetic makeup
(nature) and one's life experiences (nurture) influence one's traits
and behavior."
The extent to which the debate has been politicized can be
measured by the furor that surrounds any research indicating
there may be innate differences between the races in terms of
intelligence and abilities, or that homosexuality may be genetically
based.
Many left-wing causes favor an extreme "nurture" argument.
Radical feminists go so far as to argue that a so-called
predisposition toward motherhood or heterosexuality is actually
learned behavior. Thus they seek to deconstruct the institutions
of society, such as the family and the free market, in order to
reconstruct them to promote the 'correct' set of learned
behaviors.
Extreme "nature" arguments, such as those that claim to quantify
a genetic tendency toward infidelity, can be no less political.
Discussions of "gene therapy" or the genetic screening of children
already abound.
Another concern is the possible misuse of methodology.
The "Twin Study," upon which Spector's research is based, is a
common methodology for researchers who attempt to uncover a
significant or defining contribution of nature. The studies compare
identical with non-identical (fraternal) twins in order to look for
traits that have greater similarity in identical twins than in the non-
identical ones, whose differences make them more susceptible to
environmental factors.
Researchers then assume that the greater similarity indicates a
genetic basis for the trait, which is assigned a percentage based
on its prevalence.
Twin studies are particularly valuable in researching medical
conditions such as diabetes. But it is far from clear that the
methodology of hard science (medicine) applies with equal force
to researching soft sciences (psychology or sociology).
Volumes have been written in opposition to applying the
scientific method or mathematical measurements to human
behavior, especially in attempting to predict it, as Spector's study
seems to do.
Consider merely one objection that has specific application to
the Spector's research:
If, as Spector concludes, specific behaviors such as infidelity are
genetically based, then his conclusion calls the validity of his
research methods into question. Why? Because the home
environment is generally considered to be the primary source of
nurture-based behavior; it is a primary check on what is nature-
based. Behavior that cannot be ascribed to nurture such as
behavior learned in the home is automatically ascribed to nature.
A negative correlation is assumed.
The home environment is largely defined by the parents'
behavior. But according to Spector, that behavior may also be
genetically based. The home, therefore, ceases to be a reliable
measure of "nurture." In short, Spector's study creates a paradox
that calls itself into question.
Other reasons for approaching the "infidelity gene" with
skepticism are less philosophical. One is simply that the nature
versus nurture debate is notoriously abstract.
No clear lines of measurement have been established between
the two concepts of "nature" and "nurture." The human genome
has been sequenced, but only a small fraction of its genes are
accurately known, and even fewer have known functions.
No one knows how genes may interact. It seems premature to
say the least for anyone to talk about an "infidelity gene" let alone
to assign precise percentages to its impact on behavior.
The study smacks of sensationalism, not science.
Wendy McElroy is the editor of ifeminists.com and a research
fellow for The Independent Institute in Oakland, Calif. She is the
author and editor of many books and articles, including the new
book, "Liberty for Women: Freedom and Feminism in the 21st
Century" (Ivan R. Dee/Independent Institute, 2002). She lives
with her husband in Canada.
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